If so, why all of a sudden does this clump of matter show signs of intelligence while other collections don't?

Because the brain generates thoughts, whereas the clump of matter belonging to say, a penis, has never demonstrated any sign of what we consider thoughtfulness. Anyway, it seems we've reached the point where we are going to start chasing around in circles rather early in the discussion, and frankly, I have a room to paint.

If so, why all of a sudden does this clump of matter show signs of intelligence while other collections don't?

Because the brain generates thoughts, whereas the clump of matter belonging to say, a penis, has never demonstrated any sign of what we consider thoughtfulness. Anyway, it seems we've reached the point where we are going to start chasing around in circles rather early in the discussion, and frankly, I have a room to paint.